He's in another world, mentally transporting himself from the desk of Britain's science minister to the racing circuit at Le Mans.

Next month he will physically make the trip to achieve the ambition of a lifetime, leading his own team in what he regards as the world's greatest race, the 24-hour sports car marathon in the French town that has given its name to the punishing endurance test of man and machine.

The finance has come from his considerably deep pocket and not the science budget but not even Whitehall spin doctors searching for something positive could have envisaged positioning a partly-blind 49-year-old junior minister behind the wheel of an Aston Martin V8 Vantage filled with fuel made from wood chippings, roaring around Le Mans at 180mph to provide evidence of an administration that has rediscovered its drive.

Paul Drayson is no ordinary driver or politician. He graduated as an engineer; became involved in politics when battling animal rights extremists; sold his own life sciences business for £80m; was cleared by a parliamentary inquiry into allegations that a government contract for his business had been influenced by a £50,000 donation to the Labour Party; was accused of buying his peerage after another £500,000 donation; bought the former Gloucestershire home of Prince Michael of Kent for almost £6m; and is now in his second spell in government.

He took a "sabbatical" two years ago to pursue his passion for motor racing after serving as defence procurement minister (he denies he quit over policy differences) but was asked by Gordon Brown to cut short his life on the circuit and return as science and innovation minister in a role that allows him to attend Cabinet meetings.

He agreed on condition that he could combine his passion for motor racing with his "dream job" in the government.

Brown was sympathetic and anxious to have a minister with business experience to push the science agenda. The Prime Minister and Drayson also share the handicap of only one working eye – Drayson from birth and Brown by accident.

Drayson told Brown how much sports car racing meant to him. "It was a very personal thing. Being blind in one eye I'd been through quite a process in proving that I could do it. Having got to the highest level in sports car racing in the world there was no way I could give it up. It's part of me now."

Le Mans provides the big test for the diminutive driver who had the noise from the Brands Hatch motor racing circuit as a background accompaniment in his younger days in Kent. Can he win? He smiles: "I'm going to try my best. There's a lot of luck and you never know with Le Mans. I've certainly done my damnedest to make sure I have the best chance of doing well both in terms of fitness and commitment.

The Blairite-turned-Brownite says "Gordon was brilliant" during their talk. "I think he understood that it is important for politicians to have a hinterland, to have a life. One of the great things about doing a sport at the highest international level is that there is no debate about performance. It's not a conversation. You can either do the lap time or you can't. You can either win or you don't and it's nicely complimentary to politics."

Where is the greater sense of achievement or satisfaction, sports cars or politics? Drayson pauses. "The wonderful thing about motor racing and particularly endurance racing is you are trying your level best for an hour or two at a time. There is nothing I have experienced which is better at making you focus absolutely on being the moment and therefore feeling alive. There is nothing to touch it.

"But in terms of making a difference there is nothing that beats being in politics. You have the opportunity to really change things. Being science minister, I hope I can do it."

He is trying to shake the scientific test tube and so far has protected an aid and research budget currently running at £4bn a year.

He is predictably enthusiastic about the prospects of science helping to lead an economic and competitive recovery. "In life sciences, medicine and biotech we are number two in the world. Climate change is a challenge for the whole world – this is an area where we can make a real contribution to science, building industries for the low-carbon economy. We have a stronger set of early, life science-based businesses than we've had for 30 years so we have reason to be optimistic about our future.

"We have set out a clear vision and have put investment behind that vision. What we need this year is to move through the development and implementation of that plan. My focus as science minister is to get science recognised as important for everyone in the country, not just the relatively small group of people working in science."

He remains loyal to No 10 and dismisses suggestions of disillusionment. "I've really enjoyed the experience of trying to use the skills I developed in the private sector and applying them to government."

There have been surprises in the transition from entrepreneur to politician. "One of the important differences that really comes as a shock to people coming from the private sector is that as minister you don't get to choose the team of people that work with you. You are accountable for the development and delivery of policy but you feel that one of the most important levers you have to deliver good performance isn't open to you."

He claims to have avoided the experiences of another business leader recruited by the Prime Minister for the "government of all the talents" – Lord Digby Jones, former CBI director general and trade minister, complained that civil servants did not take some of his ideas seriously enough.

"I haven't had that experience. I have been really impressed by the quality of the civil service. Being in government has its frustrations but I have absolutely no regret, I'm happy to say, about the decision to go into politics after selling my business. I'm sure I'll look back on this time as one where I felt I had the opportunity to make a difference and did my best to do it.

"What I bring to the job is someone who has been in business for 20-odd years. I've run a business through difficult times, through recession. I've been in the position where the bank manager said to me 'you have to clear the overdraft by the end of the month, otherwise I'm putting you into receivership' and had to find a way to solve the problem. I think it's good for government to have people who have been through these things."

The mental gymnastics presented by Le Mans are never far away. The adrenaline starts flowing. "When you think about it part of the training is mental visualisation," he says. "You close your eyes and drive the car mentally." And the heart pounds. Overnight June 13 to 14 it will be "racing at about 140-150 beats a minute…"